10 is an arbitrary number. The difference between a 10 round and 12 round magazine can save a life in home defense. The difference between a 12 round and 15 round magazine can also save a life in home defense. Home invasion stats are sporadic at best but I imagine in circumstances when it is not a straight up burglary (where the perp typically knocks on the door and flees at the first sign of occupancy) but instead where they are prepared for resistance (a better definition of a home invasion) you are talking about 2+ perps.
Many many more lives are saved when law abiding citizens have access to high-capacity magazines (defined as 11+ based on everything being campaigned for here) compared to when they are banned and the bad guys will still have easy enough access to them. You guys cannot ignore the overwhelming number of instances for DGU -- argue about the exact numbers all you want, even the most conservative numbers are hundreds if not many thousands times more frequent than these mass shooting incidents.
It's been discussed ad nauseum that these mass shooting are less than a drop in the bucket in the overall picture, THAT is why I do not accept your argument. You are focusing on the wrong variable to fix a tiny subsection of a crime that is not even guaranteed to fix it as is shown from the two examples we keep rehashing.

Probably your best post since I've been in this thread... and it's not a hard argument to make.
Anti-gun-rights (1): Limiting the magazine capacity
might cause them to reload and be stopped during reload.
Pro-gun-rights (1): Limiting the magazine capacity
might cause a defensive shooter to have to reload and be killed while reloading.
Anti-gun-rights (2): Limiting the magazine capacity
might cause them to reload and be stopped during reload, preventing (arbitrary educated guess here) 10% more deaths than with a high-cap-mag in mass-shootings that result in less than 1% of US murders saving less that 0.1% of murders.
Pro-gun-rights (2): Limiting the magazine capacity
might cause them to reload and be stopped during reload, preventing (arbitrary educated guess here) 10% more deaths than with a high-cap-mag in home defense shootings that could result in less than (arbitrary guess of) 0.1% increase of successful home defense shootings.
Point being (as said before) that high cap mags save and cost lives. Which is more? Nobody can get accurate enough stats to make a good argument either way. What is the savings / cost of having to carry multiple low-cap mags vs the life savings / cost of allowing them?
Negligible. What is the cost of allowing the federal government to get their fingers deeper into restricting individual freedoms (pick your favorite Amendment - any one... speech, search and seizure, imminent domain)? I'm against more government control since there is not a convincing argument for or against magazine capacity limits. End of my discussion on the topic unless a better argument can be made.